This invention relates to floating docks comprised of one or more floating units, such as headers and fingers, constructed essentially of prestressed reinforced concrete and joined together to form a composite dock having a continuous deck and an arbitrary configuration.
Floating docks constructed of prestressed reinforced concrete float units are known. For example, see U.S. Pat. No. 3,022,759 which issued on Feb. 27, 1962, to McCall for Concrete floating Wharf. One of the advantages of concrete floating dock units is that they are well suited to resist the deteriorating action of water, especially salt water, and one of the advantages of utilizing prestressed reinforced concrete is flexibility. Prior composite dock units of this type, as explained in the above referenced patent, comprise horizontal, resilient slabs, also referred to as decks, of prestressed reinforced concrete and pontoons rigidly connected to the underside of the slabs to provide floatation.
One of the problems with such prior art composite docks is that their length is limited, inter alia, because of the flexibility of the slab. For example, when the slab has floatation pontoons attached to its lower surface at points about one quarter slab length from each end, the center portion and the end portions are unsupported and will sag. Further, and more importantly, the wave action will produce enormous stresses on the slab with severe displacement of the unsupported and cantilevered slab portion. To prevent such sagging and wave action motion of slab portions, either the slab must be made thick enough so that it loses some of its flexibility, or the length of the slab must be short enough to prevent excessive bending. Further, the flexibility of such a prior art slab does cause hairline cracks in the cement which allows water, and particularly salt water, to reach the prestressed tendons causing the same to deteriorate under the corrosive action of the water.
It is therefore a primary object of the present invention to provide a concrete floatation unit that is longer in length, per unit, than was possible heretofore which results in greater economy since the cost of a larger unit is less than the cost of two units each one-half of the length of the larger unit.
It is another object of the present invention to provide a concrete floatation dock unit which has a weight per unit length which is less than those of prior art units and therefore more economical to fabricate and to transport to the dock area.
In another object of the present invention to provide a concrete floatation unit for assembling into a dock which is rigid to prevent the formation of hairline cracks and the resulting exposure of the tendons to the corrosive action of the sea water, which is economical and which allows assembly with additional floatation units.
It is a still further object of the present invention to provide concrete floatation units which allow for the installation of a dock in areas in which docks could heretofore not be installed due to high wave action and which are sufficiently strong to withstand such wave action.
It is another object of the present invention to provide a means of connecting concrete floatation units to one another which is flexible, economical and very secure against dislodgment, and which is well able to withstand lateral forces, such as are caused by flooding and by the tides and by wind forces acting against boats tide thereto.